MDEV-28576 RENAME COLUMN with NOCOPY algorithm leads to corrupt partitioned table

10.5 part: test cases and comments.
The code is in the merge commit 74fe1c44aa

When f.ex. table is partitioned by HASH(a) and we rename column `a' to
`b' partitioning filter stays unchanged: HASH(a). That's the wrong
behavior.

The patch updates partitioning filter in accordance to the new columns
names. That includes partition/subpartition expression and
partition/subpartition field list.

mysql-test/main/partition_alter.result

@@ -212,3 +212,81 @@ test.t	check	status	OK
 delete from t order by b limit 1;
 drop table t;
 # End of 10.3 tests
+#
+# MDEV-28576 RENAME COLUMN with NOCOPY algorithm leads to corrupt partitioned table
+#
+create table t (a int)
+partition by list (a)
+subpartition by hash(a) subpartitions 2
+(partition p0 values in (1));
+alter table t rename column a to b, algorithm=nocopy;
+show create table t;
+Table	Create Table
+t	CREATE TABLE `t` (
+  `b` int(11) DEFAULT NULL
+) ENGINE=MyISAM DEFAULT CHARSET=latin1 COLLATE=latin1_swedish_ci
+ PARTITION BY LIST (`b`)
+SUBPARTITION BY HASH (`b`)
+SUBPARTITIONS 2
+(PARTITION `p0` VALUES IN (1) ENGINE = MyISAM)
+alter table t rename column b to c, algorithm=copy;
+show create table t;
+Table	Create Table
+t	CREATE TABLE `t` (
+  `c` int(11) DEFAULT NULL
+) ENGINE=MyISAM DEFAULT CHARSET=latin1 COLLATE=latin1_swedish_ci
+ PARTITION BY LIST (`c`)
+SUBPARTITION BY HASH (`c`)
+SUBPARTITIONS 2
+(PARTITION `p0` VALUES IN (1) ENGINE = MyISAM)
+drop table t;
+create table t (d int, e int)
+partition by list columns (d, e)
+subpartition by key (d, e)
+(partition p0 values in ((2, 3)));
+alter table t rename column d to f, rename column e to g, algorithm=nocopy;
+show create table t;
+Table	Create Table
+t	CREATE TABLE `t` (
+  `f` int(11) DEFAULT NULL,
+  `g` int(11) DEFAULT NULL
+) ENGINE=MyISAM DEFAULT CHARSET=latin1 COLLATE=latin1_swedish_ci
+ PARTITION BY LIST  COLUMNS(`f`,`g`)
+SUBPARTITION BY KEY (`f`,`g`)
+(PARTITION `p0` VALUES IN ((2,3)) ENGINE = MyISAM)
+alter table t rename column f to h, rename column g to i, algorithm=copy;
+show create table t;
+Table	Create Table
+t	CREATE TABLE `t` (
+  `h` int(11) DEFAULT NULL,
+  `i` int(11) DEFAULT NULL
+) ENGINE=MyISAM DEFAULT CHARSET=latin1 COLLATE=latin1_swedish_ci
+ PARTITION BY LIST  COLUMNS(`h`,`i`)
+SUBPARTITION BY KEY (`h`,`i`)
+(PARTITION `p0` VALUES IN ((2,3)) ENGINE = MyISAM)
+drop table t;
+create table t (k int, l int)
+partition by range (k)
+subpartition by hash(l) subpartitions 4
+(partition p0 values less than (5));
+alter table t rename column k to l, rename column l to k;
+show create table t;
+Table	Create Table
+t	CREATE TABLE `t` (
+  `l` int(11) DEFAULT NULL,
+  `k` int(11) DEFAULT NULL
+) ENGINE=MyISAM DEFAULT CHARSET=latin1 COLLATE=latin1_swedish_ci
+ PARTITION BY RANGE (`l`)
+SUBPARTITION BY HASH (`k`)
+SUBPARTITIONS 4
+(PARTITION `p0` VALUES LESS THAN (5) ENGINE = MyISAM)
+drop table t;
+create table t (a int, b int) partition by list (b) (partition p1 values in (1, 2));
+insert into t values (0, 1), (2, 2);
+alter table t rename column b to f, rename column a to b, algorithm=nocopy;
+check table t;
+Table	Op	Msg_type	Msg_text
+test.t	check	status	OK
+delete from t order by b limit 1;
+drop table t;
+# End of 10.5 tests

mysql-test/main/partition_alter.test

@@ -204,3 +204,44 @@ delete from t order by b limit 1;
 drop table t;
 
 --echo # End of 10.3 tests
+
+--echo #
+--echo # MDEV-28576 RENAME COLUMN with NOCOPY algorithm leads to corrupt partitioned table
+--echo #
+create table t (a int)
+partition by list (a)
+subpartition by hash(a) subpartitions 2
+(partition p0 values in (1));
+alter table t rename column a to b, algorithm=nocopy;
+show create table t;
+alter table t rename column b to c, algorithm=copy;
+show create table t;
+drop table t;
+
+create table t (d int, e int)
+partition by list columns (d, e)
+subpartition by key (d, e)
+(partition p0 values in ((2, 3)));
+alter table t rename column d to f, rename column e to g, algorithm=nocopy;
+show create table t;
+alter table t rename column f to h, rename column g to i, algorithm=copy;
+show create table t;
+drop table t;
+
+create table t (k int, l int)
+partition by range (k)
+subpartition by hash(l) subpartitions 4
+(partition p0 values less than (5));
+alter table t rename column k to l, rename column l to k;
+show create table t;
+drop table t;
+
+create table t (a int, b int) partition by list (b) (partition p1 values in (1, 2));
+insert into t values (0, 1), (2, 2);
+alter table t rename column b to f, rename column a to b, algorithm=nocopy;
+check table t;
+delete from t order by b limit 1;
+# cleanup
+drop table t;
+
+--echo # End of 10.5 tests

sql/field.h

@@ -5661,7 +5661,7 @@ inline bool Row_definition_list::eq_name(const Spvar_definition *def,
 class Create_field :public Column_definition
 {
 public:
-  LEX_CSTRING change;			// If done with alter table
+  LEX_CSTRING change;			// Old column name if column is renamed by ALTER
   LEX_CSTRING after;			// Put column after this one
   Field *field;				// For alter table
   const TYPELIB *save_interval;         // Temporary copy for the above

sql/partition_info.h

@@ -79,6 +79,10 @@ struct Vers_part_info : public Sql_alloc
   partition_element *hist_part;
 };
 
+/*
+  See generate_partition_syntax() for details of how the data is used
+  in partition expression.
+*/
 class partition_info : public Sql_alloc
 {
 public:
@@ -88,6 +92,10 @@ public:
   List<partition_element> partitions;
   List<partition_element> temp_partitions;
 
+  /*
+    These are mutually exclusive with part_expr/subpart_expr depending on
+    what is specified in partitioning filter: expression or column list.
+  */
   List<const char> part_field_list;
   List<const char> subpart_field_list;
   

sql/sql_partition.cc

@@ -4801,6 +4801,7 @@ static void check_datadir_altered_for_innodb(THD *thd,
   @param[out] partition_changed  Boolean indicating whether partition changed
   @param[out] fast_alter_table   Boolean indicating if fast partition alter is
                                  possible.
+  @param[out] thd->work_part_info Prepared part_info for the new table
 
   @return Operation status
     @retval TRUE                 Error

sql/sql_table.cc

@@ -10535,6 +10535,9 @@ do_continue:;
 
 #ifdef WITH_PARTITION_STORAGE_ENGINE
   {
+    /*
+      Partitioning: part_info is prepared and returned via thd->work_part_info
+    */
     if (prep_alter_part_table(thd, table, alter_info, create_info,
                               &partition_changed, &fast_alter_partition))
     {
@@ -10712,6 +10715,9 @@ do_continue:;
   else
     alter_info->flags|= ALTER_INDEX_ORDER;
   create_info->alias= alter_ctx.table_name;
+  /*
+    Partitioning: part_info is passed via thd->work_part_info
+  */
   error= create_table_impl(thd, alter_ctx.db, alter_ctx.table_name,
                            alter_ctx.new_db, alter_ctx.tmp_name,
                            alter_ctx.get_tmp_path(),